1. Field of the Invention
The present invention relates to an encapsulating device for electronic circuitry as well as to a battery pack.
2. Technical Background
Encapsulating devices are extensively used within the micro-electronics industry such as to protect one or more integrated electronic circuits, abbreviated with IC, placed within this encapsulating device, and to allow connections from leads of another component on for instance a printed circuit board, to be made with the inner pads of the integrated circuit itself. The leads of the encapsulating devices in this way allow to connect the inner pads of the electrical circuitry within the encapsulating device physically to other circuitry external to this encapsulating device. Encapsulating devices are available in a lot of different embodiments, all serving particular purposes. Yet a characteristic property of all of them is that the pins of these encapsulating devices, serving to contact the encapsulating device to an external component on for instance a printed circuit board, are such that adhesion to another conductor such as pins or conductors on a printed board, always occurs via another material such as soldering, using solder paste or conductive glue.
For the special case of protection circuits used in battery packs, whereby an input pin of such a protection circuit is to be coupled, usually via a thin metal plate or strip, to one the leads of a battery, and an output of this protection circuit is to be connected with other circuitry for portable applications, for instance telephone circuitry in a cellular phone, this protection circuit is generally placed on a printed circuit board. This is for instance described in U.S. Pat. No. 6,184,658. In order to reduce cost and weight, IC's and transistors are mounted as bare chips on this board, whereby this circuit board is further completely sealed on one side, thereby providing a shield against moisture and mechanical damage. Dedicated pads or external connecting terminals are formed on the surface opposite to the part-mounting surface of this printed circuit board. The metal strips used for coupling the dedicated pads of this printed circuit board to the leads of the battery (both not shown in U.S. Pat. No. 6,184,658) are usually soldered to these dedicated pads . These metal strips are further attached to the leads of a battery. A schematic of such a prior art battery pack is shown in FIG. 1. In this FIG. 1, the metal case of the battery forms one lead of the battery which is indicated as L2 while the other lead of the battery B is indicated with L1. The PCB whereon the protection circuitry, in this prior art case composed of several IC's and some discrete components, is placed, is denoted PCB. C1 and C2 denote the terminals of the battery pack to further functional circuits, for instance telephone or computer circuits. C2 may thereby be directly coupled to the battery case, whereas C1 may be coupled via a contact pin on a flexible connection, abbreviated with Flex PC, to a dedicated pad C of the PCB. The connection between pad C and the flex PC contact is also realized via solder. Other dedicated pads P1 and P2 of this Printed circuit board are soldered to the metal strips for further coupling to the battery leads, such as is also indicated on FIG. 1.
In such a prior art battery pack as depicted on FIG. 1, the sealed PCB could thus as well be considered as an encapsulating device for the protection circuitry. Again also in this special case, the terminals on the PCB, are always connected via additional material such as solder paste or conductive glue to a metal strip, or contact on a flexible connection.
This prior art situation is, although it made use of bare integrated circuits to save cost and weight, still space consuming. Moreover, a PCB is to be foreseen for each battery pack, and the assembly of the PCB itself as well as the forming of the solder connections to the battery pack is expensive.